Rapid development in communication field, particularly in consumer electronics field, makes requirement of a consumer on consumer electronics relavent products higher and higher, super-thin products emerge endlessly. As a key component of the consumer electronic products, miniaturization and multiple frequency bands of an antenna always lead designers of the antenna ceaselessly contemplations and improvements. How an antenna desired by the product can be designed under a limited space is one of subjects which are most popular at present. At present, multiple frequency band antennas have a deficiency on a given size, which cannot meet the requirement of the super-thin products. For example, a multiple frequency band ceramic antenna launched on the market uses three metal radiation portions to realize the desired frequency bands and uses a direct feed mode. However, as such, not only a size is limited, but also a bandwidth is very difficult to meet full frequency band required by the long term evolution (LTE). Therefore, it can be seen that designing a miniaturization multiple frequency band antenna definitely is a tendency in future.
In patent CN102623801, a direct feed design is used, which results in a deficiency that a communication frequency band is relative narrow. In order to widen the communication frequency band, it requires to increase more radiation portions, thereby resulting in complexity of the antenna structure in design and manufacturing.
In patents CN102683829, CN104701609 and CN103403962, although a coupling feed mode is used, antenna structures disclosed in those patents all take a coupling portion as a certain radiation portion, in other words, the coupling portion has the function of the radiation portion. As such, it is not beneficial to optimize an overall performance of the antenna. Because when a length of the coupling portion is adjusted, impedances of other radiation portions will be also affected due to this adjustment. Therefore, deficiencies of the antenna devices in those patents lie in that a volume of the antenna device is relative large, and a design of the antenna device is relative complex.
The description in background as above merely is used to provide a background art, and it does not admit that the description on the background art as above discloses the object of the present disclosure, and do not constitute a prior art of the present disclosure, and any description in background as above shall not be acted as any part of the present disclosure.